Gay, lesbian, bisexual, and questioning (GLBQ) youth are at increased risk for health disparities, including HIV and teen pregnancy, vs. heterosexual peers, a risk attributed to the effects of nearly universal stigma for sexual minorities. Behaviors in a social group that convey or enforce stigma are enacted stigma; culture influences stigma, yet gender and ethnic variations in enacted stigma have seldom been examined among youth. Enacted stigma in school has been measured only indirectly in large-scale school-based surveys. To develop effective interventions, we need to understand enacted stigma among different cultural groups, develop culturally competent, reliable measures, and test the links between stigma and health behaviors in population-based surveys. Although GLBQ stigma is our primary focus, understanding how other types of stigma are enacted is important in developing general measures of enacted stigma. Therefore, the purpose of this 5-year, mixed-methods international study is to explore enacted stigma behaviors among indigenous, Asian-ancestry, and European-ancestry adolescents in school environments in Canada, New Zea- land, and the US, to develop cross-cultural measures of enacted stigma for adolescent health surveys, and to examine the association of types of stigma and HIV risk behaviors among adolescents. The specific aims are: I. To compare the prevalence of HIV risk behaviors associated with sexual orientation and other stigmatized identi- ties among youth in existing large-scale school-based surveys, and to identify both the existing indirect measures of stigma that are risk factors plus the protective factors significantly associated with the HIV risk behaviors. II. To identify the prevalence of HIV risk behaviors and associated risk and protective factors among indigenous adolescents--American Indian (US), First Nations (Canada), Maori (New Zealand--as well as youth of Asian ancestry in each country, and to compare the patterns among adolescents of similar ethnic backgrounds in the 3 countries. III. To explore among adolescent and adult key informants the ways stigma is understood, assigned, and enforced in the school environment, and to compare the patterns within the three countries. This exploration will be focused pri- marily on stigma based on sexual orientation status, but other types of stigmatized identities will be examined to under- stand the similarities and differences of how stigma is enacted, and the potential utility of generic stigma measures. IV. Within each country, to elicit explanatory models from adolescents and youth workers on the survey findings of HIV risk behaviors and stigma, and to tap suggested strategies for reducing stigma and addressing sexual risk behaviors in culturally appropriate ways among GLBQ youth. V. Incorporating the findings of aims I-IV, to develop, pilot, and psychometrically evaluate universal and country- specific culturally competent items and scales, for population-based adolescent health surveys, that measure perceived and enacted stigma in school, to allow cross-cul_ral comparisons of the effects of stigma among adolescents.